A training program consistent with the objectives of the Clinical Investigator Award is described which affords the candidate continued training in experimental pulmonary physiology. It is supervised by J.B. West M.D., Ph.D., Professor of Medicine and Bioengineering, University of California-San Diego, and emphasizes the mathematical modeling of pulmonary function, its experimental verification, and its application to pulmonary disease. The program builds upon the candidate's previous clinical training and his training in mathematicas and applied mechanics. The central research project offers new, basic information having a direct bearing on the mechanism of high frequency ventilation by extending the fundamental work of Haselton and Scherer to the asymmetric geometry of the conducting airways. It uses a computer model of the airway system based upon the fluid mechanics of airflow to evaluate the effects on oscillatory gas transport of changes in airway bifurcation geometry, gas diffusivity, and the frequency and amplitude of oscillation. Its predictions are tested experimentally in physical models of airway bifurcations and in the isolated dog lung. The model allows computation of an effective diffusivity which incorporates the specific velocity field in the airways and thus separates the roles of molecular diffusion and convective streaming in oscillatory gas transport. The project thus offers some resolution of the competing theories of high frequency ventilation and thereby contributes to its clinical application.